3 Answers
3

I assume you mean the roof is exposed to the sun...and that in turn is heating your ceiling?

If so, options:

make sure the roof is reflective (white/metallic) rather than a dark color (which absorbs heat)

make sure the roof is insulated

If the roof can support a green/planted roof, consider that.

plant trees to shade the roof (obviously may take a few decades to fully work)

create a cold roof (some form of secondary roof to shade the one below...in many climates this would be an attic type constructions...but almost anything could work...a covered roof deck, for instance--or even just a vented second layer such as standing seam metal panels on top of spacers to allow for airflow underneath.)

Once the ceiling is warm, it means the heat had already entered the living space. Can't really cool the ceiling at that point without getting the heat out of the living space. Exhaust fans could help...along with perhaps a ceiling fan. Cross ventilation with windows/vents. Etc.

Those tips are great.. but in winter it will be really cold. Looking at Wikipedia. it can get cold.. So i would not advise doing all this.
–
ppumkinMar 30 '12 at 15:35

A properly insulated and vented roof should not contribute much to cooling nor heating.
–
DA01Mar 30 '12 at 16:57

I live in the Canary Islands where it's always sunny and we don't need heating. We painted the flat roof of our house white and while it made a difference in summer - it was definitely cooler and more comfortable - it can be a little cold in the winter now.
–
markMar 31 '12 at 19:13

You also want to ventilate the attic space. If there is a space between the ceiling and the roof, its going to get pretty hot in there. In our house it can get above 190 °F.

You can get gable mounted fans that suck in air from outside (at 100 °F, or what ever temperature it is outside) and force the 190 °F air out of the attic.

Another thing to consider: at about 7pm at night the outside air can cool down considerably, enough so that the house is now warmer than the outside. Instead of opening doors and windows I installed a separate switch controlled whole-house fan. It connects from the ceiling to the attic. You open a window, then turn on the fan. It sucks the cooler air in through the window, taking the warmer air in the house and pushing it into the attic. Then the attic air gets pushed out of the attic vents. So your attic gets cooler too. I can get my house from 80+ °F to 70+ °F within 10 minutes this way.

I live in a desert, sometimes the hottest place in the USA, beating Death Valley. Lots of people here use evaporative coolers, or what we call swamp coolers. If you live in a humid area, then forget it because swamp coolers cool by putting a cool dampness in the air, nothing wet but on a hot dry day a properly sized cooler can cool a 2000 square foot as much as 25 degrees. While this costs money, the 'green' part about them is that they save up to 80% when compare to air conditioners.

The way it would work after installation is you open a door or window and start the cooler. The cooling comes with the pressure built up in your house. The more windows and doors open the less pressure. Too much pressure is a bad thing for your motor, so always leave a window cracked.

With just a motor load, no compressors a lot of money can be saved compared to an A/C. They come in wall mount, window mount, roof mount, portable (on rollers) or just fans with a misting system. The small fans will only cool you if you are sitting right in front of it.

Put green landscaping around windows, like bushes or shrubs, to cool the air more when windows are open. On the hot side of the house plant trees to provide shade when the trees grow tall. These might not have immediate affects on your house, but will cool you more when the plants mature.